Aims: 1) To examine the relation between maternal serum levels of the androgenic DDT metabolite DDE in relation to anogenital distance in 200 male newborns in Tapachula, Mexico, where there has been recent, high-level exposure to DDT, 2) To conduct a pilot study of the relation of maternal DDE levels to risk of preterm birth (n=75 cases, 150 controls). Accomplishments: The study should go into the field in July of 2001. Pilot data have confirmed the high exposure levels and the feasibility of measuring anogenital distance in Mexico.